Photometric response of a very small, stoichiometric hydrogen-air flame to compounds of the iron group

In contrast to the typical, strongly hydrogen-rich flame of the flame photometric detector (FPD), a very small, stoichiometric flame (using around 16 ml/min H-2 and 40 ml/min air) yields high sensitivity for elements of the iron group. The small, stoichiometric flame's response to gas chromatographic peaks of ferrocene, ruthenocene and osmocene is mostly, if not exclusively, due to spectral continua. The minimum detectable flows [for a signal-to-noise ratio of two, with noise measured peak-to-peak at a 1-s RC (resistancexcapacitance) time constant] are 3.10(-15), 4.10(-16) and 1.10(-15) mol of metal per second for Fe, Ru and Os, respectively. For the typical case of osmocene, the linear range measures about five orders of magnitude, and the atomic selectivity of Os/C is about 4.5. (C) 1998 Published by Elsevier Science B.V.